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102 terms

Ventilation Work Book

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The pressure difference between two points in a tube or vessel is called the
Driving Pressure
The barometric pressure difference between the mouth pressure and the alveolar pressure is called the
Transairway Pressure
When the pressure is greater within the airway, the pressure is called
Positive transmural pressure
When the pressure is greater outside the airway, the pressure is called
Negative transmural pressure
The difference between the alveolar pressure and the pleural pressure is called the
Transpulmonary pressure (Ptp)
If the gas pressure at the beginning of a vessel is 12 mm Hg and the pressure at the other end of the same vessel is 7 mm Hg, What is the driving pressure?
5 mm Hg
The difference between the alveolar pressure and the body surface pressure is called the
Thransthoracic Pressure (Ptt)
If the Palv is 751 mm Hg and the Pm is 758 Hg, what is the Pta?
7 mm Hg
If the Ppl is 752 mm Hg and the Palv is 748 mm Hg, what is the Ptp?
4 mm Hg
If the Palv is 751 mm Hg and the Pbs is 757 mm Hg, what is the Ptt?
6 mm Hg
During inspiration, the thoracic volume increases and the intrapleural and intra-alveolar pressures ______.
decreases
During expiration, the intra-alveolar pressure is ______ than the barometric pressure
greater
During a normal expiration, the intrapleural pressure is always ______the barometric pressure
below
The normal intrapleural pressure change is about ___ to ___ cm H2O pressure, or ___ to ___ mm Hg.
3,6 and 2,4
Lung compliance is defined as the change in lung _______ per change in _______.
volume and pressure
If an individual generates an intrapleural pressure of -7 cm H2O during inspiration, and the lungs accept a new volume of 385 ml of air; what is the compliance of the lungs?
0.055 L/cm H2O or (55ml cm H2O)
If the same patient, four hours later, generates an intrapleural pressure of -5 cm H2O during inspiration, and the lungs accept a new volume of 350 ml of air, what is the compliance of the lungs?
0.07 L/cm H2O or (70 ml cm H2O)
If a mechanical ventilator generates a +9 cm H2O pressure during inspiration and the lungs accept a new volume of 450 ml of gas, what is the compliance of the lungs?
0.050 L / cm H2O or (50ml/cm H2O)
If, on the same patient six hours later, the mechanical ventilator generates a + 15 cm H2O pressure and the lungs accept a new volume of 675 ml of gas, what is the compliance of the lungs?
0.045 L/cm H2O or (45ml/cm H2O)
Under normal resting conditions, the average lung compliance during each breath is approximately...
0.1 L/cm H2O
According to the volume-pressure curve, if an individual has a resting lung volume of 1500 ml, and generates a negative 25 cm H2O pressure (in addition to the negative pressure required to maintain the resting lung volume), how many ml of gas will the lungs accommodate (in addition to the resting lung volume)?
2000 ml (2L)
When the lung compliance decreases, the volume-pressure curve moves to the_____
right
When the volume-pressure curve moves to the left, lung compliance is
Increased
As the alveoli approach their total filling capacity, lung compliance______
decreases
Elastance is defined as
The natural ability of matter to respond directly to force and to return to its original resting position or shape after the external force no longer exists.
In pulmonary physiology, elastance is defined as ____________and is expressed as_________:
The change in pressure per change in volume, and ΔP / ΔV
Lungs with high compliance have ______ elastance, and lungs with low compliance have _____ elastance.
low, high
Hooke's law states that
When a truly elastic body, like a spring, is acted on by 1 unit of force, the elastic body will stretch 1 unit of length, and when acted on by 2 units of force it will stretch 2 units of length, and so forth.
When Hooke's law is applied to the elastic properties of teh lungs, _______ is substituted for length and _______ is substituted for force.
volume, pressure
The molecular, cohesive force at the liquid-gas interface is called
surface tension
The liquid film that lines the interior surface of the alveoli has the potential to exert a force of ________
70 dynes/cm
When Laplace's law is applied to a sphere with one liquid-gas interface, the equation is written as follows:
P= 2ST / r
The mathmatical arrangement of Laplace's law shows that the distending pressure of a liquid bubble is
a. directly proportional to the surface tension of the liquid
b. inversely proportional to the radius of the sphere
According to Laplace's law, as the surface tension of a liquid bubble increases, the distending pressure required to hold the bubble open ______; and as the radius of the bubble increases, the destending pressure ________.
increases, decreases
When two different-sized bubbles with the same surface tension are in direct communication what happens
The smaller bubble will empty into the larger bubble
During the formation of a new bubble, the principles of Laplace's law do not come into effect until the distending pressure of the liquid sphere goes beyond the what?
Critical opening prssure
As a liquid bubble increases in size, the surface tension does what?
remains the same
Pulmonary surfactant is produced by what
alveolar type II cells
The surfactant molecule has both a hydrophobic end, which means it ____________, and a hydrophilic end, which means it is ________________.
water insoluble (hating), and water soluble (loving)
In the healthy lung, when the alveolus decreases in size, the amount of surfactant to alveolar surface area ________. This action causes the alveolar surface tension to ___________.
increase, decrease
It is estimated that the surface tension of the average alveolus varies from ___________ in the small alveolus to about _____________ in the fully distended alveolus.
5-15 dynes, and 50 dynes
List some general causes of surfactant deficiency
a. acidosis
b. hypoxia
c. hyperoxia
d. atalectasis
e. pulmonary vascular congestion
In the healthy lung, both the elastic force and the surface tension force are _____ in the small alveolus
low
The term dynamic is defined as the
study of forces in action
In the lungs, dynamic refers to
the movement in action of gas in and out of the lungs and the pressure changes required to move the gas
When Poiseuille's law is arranged for flow V, it is written as follows:
V = Δ Pr₄ π / 81 ŋ
According to Poiseuille's law, and assuming all other variables remain the same what all will happen to flow?
a. as the pressure increases, flow increases
b. as the length of a tube decreases, flow increases
c. as the radius of a tube increases, flow increases
d. as the viscosity decreases, flow increases
Using Poiseuille's law equations and assuming all other variables remain the same:
If the radius of a tube that has gas flowing through it at 32 liters per minute (L/min) is reduced by 50 % of its original size, what will be the new gas flow through the tube?
2 L/min
Using Poiseuille's law equations and assuming all other variables remain the same:
If the radius of a tube that has gas flowing through it at 28 L/min is reduced by 16%, what will be the new gas flow through the tube?
14 L/min
Using Poiseuille's law equations and assuming all other variables remain the same:
If the radius of a tube that has a driving pressure of 16 cm H2O is reduced by 50% of its original size, waht will be the new driving pressure required to maintain the same gas flow through the tube?
256 cm H2O
Using Poiseuille's law equations and assuming all other variables remain the same:
If the radius of a tube that has a driving pressure of 10 cm H2O is reduced by 16% of its original size, what will be the new driving pressure required to maintain the same gas flow through the tube?
20 cm H2O
Using Poiseuille's law equations and assuming all other variables remain the same:
If the radius of a tube that has gas flowing through it is at 160 L/min is decreased by 50% of its original size, what will be the new gas flow through the tube?
10 L/min
Using Poiseuille's law equations and assuming all other variables remain the same:
If the radius of a tube that has gas flowing through it at 100 L/min is decreased by 16% of its original size, what will be the new gas flow through the tube?
50 L/min
Using Poiseuille's law equations and assuming all other variables remain the same:
If the radius of a tube that has a driving pressure of 10 cm H2O is decreased by 50% of its original size, what will be the new driving pressure required to maintain the same gas flow through the tube?
160 cm H2O
Using Poiseuille's law equations and assuming all other variables remain the same:
If the radius of a tube that has a driving pressure of 5 cm H2O is decreased by 16% of its original size, what will be the new driving pressure required to maintain the same gas flow through the tube?
10 cm H2O
Write the simple proportionalities of Poisuille's law for flow (V) and pressure (P):
V = Pr₄
P = V / r₄
Airway resistance (Raw) is defined as the
pressure difference between the mouth and the alveoli divided by flow rate
Write the equation for airway resistance (Raw) and include the units of measurement:
Raw = ΔP (cm H2O) / V (L/sec)
If a patient produces a flow rate of 10 liters per second (L/sec) during inspiration by generating a transairway pressure (Pta) of 30 cm H2O, what is the patient's Raw?
3cm H2O/L/sec
The normal Raw in the tracheobroncial tree is about ___ to ___ cm H2O/L/sec
0.5, 1.5
Laminar gas flow refers to
a gas flow that is steamlined
Turbulent gas flow refers to
molecules that move through a tube in a random flow
Time constant is defined as the
time (in seconds) necessary to inflate a particular lung region to about 60 % of its potential filling capacity
Lung regions that have an increased airway resistance require
more time to inflate
Lung regions that have an increased compliance require
more time to inflate
Which of the following causes lung regions to have a long time constant
a. increased lung compliance
b. increased airway resistance
Lung regions that have a decreased airway resistance require
less time to inflate
Lung regions that have a decreased compliance require
less time to inflate
Which of the following causes lung regions to have a short time constant?
a. decreased lung compliance
b. decreased airway resistance
Dynamic compliance is defined as the
change in the volume of the lungs divided by the change in the transpulmonary pressure during the time required for one breath.
In the normal lung, the dynamic compliance is ______ lung compliance at all breathing frequencies
equal to
In the partially obstructed airways, the ratio of dynamic compliance to lung compliance ___________ as the breathing frequency increases
remains the same
Frequency dependent refers to
alveoli distal to an obstruction that do not have enough time to fill their potential filling capacity as the breathing frequency increases.
The ventilatory pattern consists of the following three components
a. tidal volume
b. ventilatory rate
c. time relationship between inhalation and exhalation
Normal tidal volume is about ___ to ____ mL/kg; or ___ to ___ mL/lb.
7,9 and 3, 4
normal adult ventilatory rate is about ____ breaths per minute
15
the normal I:E is about
1:2
The gas that reaches the alveoli during inspiration is referred to as
Alveolar ventilation
The gas that does not reach the alveoli during inspiration is referred to as
dead space ventilation
Anatomic dead space is defined as
the volume of gas in the conducting airways:
nose, mouth, pharynx, larynx, and lower airways down to, but not including the respiratory bronchioles
If a patient weighs 130 pounds, about how many milliliters (mL) of inspired gas during each breath would be an anatomic dead space gas?
130 mL
Alveolar ventilation is equal to the _________ minus the ________________ multiplied by the ______________
tidal volume, dead space ventilation, breaths per minute
An individual presents with this data:
*Vt = 575 mL
*Vd = 185 mL
*Breaths/minute = 16
What is the alveolar ventilation?
6240 mL
Alveolar dead space is defined as
an alveolus that is ventilated but not perfused with pulmonary blood
Physiologic dead space is defined as
the sum of the anatomic dead space and the alveolar dead space
In the upright position, the negative intrapleural pressure at the apex of the lung is normally_____than at the base?
greater
In the upright position, the alveoli in the upper lung regions are _____ in size compared to the alveoli in the lower lung regions?
larger
In the upright lung, ventilation is much greater in which area?
lower lung regions
When lung complaince decreases, the patient's ventilatory rate generally ____ and the tidal volume ______
increases, decreases
When airway resistance increases, the patient's ventilatory rate generally _____ and the tidal volume _______
decreases, increases
In response to a certain respiratory disorder, the patient may adopt a ventilatory pattern based on the expenditure of ______ rather than the efficiency of __________
energy, ventilation
Apnea is defined as
the complete absence of spontaneous ventilation
Eupnea is defined as
normal, spontaneous breathing
Biot's breathing is defined as
short episodes of rapid, uniformly deep inspirations, followed by 10-30 sec of apnea
Hyperpnea is defined as
increased depth of breathing with or without an increased frequency
Hyperventilation is defined as
an increased alveolar ventilation produced by any ventilatory patter that causes the PACO2 and, therefore, the PaCO2 to decrease
Hypoventilation is defined as
a decreased alveolar ventilation produced by any ventilatory pattern that causes the PACO2 and, therefore, the PaCO2 to increase
Tachypnea is defined as
a rapid breathing rate
Cheyne-stokes breathing is defined as
10-30 sec of apnea, followed by a gradual increase in the volume and frequency of breathing, followed by a gradual decrease in the breathing until another period of apnea occurs
Kussmaul breathing is defined as
(diabetic) both an increased depth and rate of breathing
Orthopnea is defined as
a condition in which an individual is able to breathe most comfortably in the upright position
Dyspnea is defined as
difficulty in breathing, of which the individual is consciously aware.